Ring opening of epoxides with alcohols using Fe(Cp)2BF 4 as catalyst

Article abstract of DOI:10.1016/j.tetlet.2014.05.017

Fe(Cp)₂BF₄ is an efficient catalyst for the alcoholysis of aromatic, aliphatic, and cyclic epoxides giving excellent yields of the corresponding β-alkoxy alcohols under ambient conditions. The methanolysis of styrene oxide using Fe(Cp)₂BF₄ as a catalyst (5 mol %) gave excellent yield of 2-methoxy-2-phenylethanol with complete regio-selectivity. The ring opening of cyclic epoxides gave 77-97% yields of trans-β-methoxy alcohols, in 0.5-6 h. The use of 1,2-epoxyhexane and 1,2-epoxydodecane as substrates gave both regioisomers in excellent yields. The first order rate of reaction with respect to catalyst was observed for the kinetics of ring opening of 1,2-epoxyhexane with methanol.

Full text of DOI:10.1016/j.tetlet.2014.05.017

Tetrahedron Letters xxx (2014) xxx–xxx
Contents lists available at ScienceDirect
Tetrahedron Letters
journal homepage: www.elsevier.com/locate/tetlet
Ring opening of epoxides with alcohols using Fe(Cp)2BF4 as catalyst
⇑
Geeta Devi Yadav, Surendra Singh
Department of Chemistry, University of Delhi, Delhi 110007, India
a r t i c l e i n f o
a b s t r a c t
Article history:
Fe(Cp)2BF4 is an efficient catalyst for the alcoholysis of aromatic, aliphatic, and cyclic epoxides giving
excellent yields of the corresponding b-alkoxy alcohols under ambient conditions. The methanolysis of
styrene oxide using Fe(Cp)2BF4 as a catalyst (5 mol %) gave excellent yield of 2-methoxy-2-phenylethanol
with complete regio-selectivity. The ring opening of cyclic epoxides gave 77–97% yields of trans-b-meth-
oxy alcohols, in 0.5–6 h. The use of 1,2-epoxyhexane and 1,2-epoxydodecane as substrates gave both
regioisomers in excellent yields. The first order rate of reaction with respect to catalyst was observed
for the kinetics of ring opening of 1,2-epoxyhexane with methanol.
Received 15 March 2014
Revised 3 May 2014
Accepted 7 May 2014
Available online xxxx
Keywords:
Ring opening of epoxides
Alcoholysis
Ó 2014 Elsevier Ltd. All rights reserved.
Methanolysis
Fe(Cp)2BF4
Lewis acid catalyst
The ring opening of epoxides with various nucleophiles gives a
variety of 1,2-disubstituted compounds.1 b-Alkoxy alcohols are
valuable intermediates in the direct synthesis of b-alkoxy ketones2
and also this functionality is present in some natural products.3
The ring opening of epoxides with alcohols requires either strongly
acidic or basic conditions due to the poor nucleophilicity of alco-
hols.4 The harsh conditions associated with this process have pro-
vided the impetus to develop mild methodologies.
Fe
BF4
Fe
PF6
Fe(Cp)2PF6
Fe(Cp)2BF4
Figure 1. Structure of catalysts.
Various heterogeneous catalysts5 have been successively devel-
oped for the ring opening of epoxides with primary alcohols. Sim-
ple, general and efficient catalysts for the alcoholysis of epoxides
have also been developed using transition metals and lanthanides
salts,6 porphyrin metal complexes,7 salen and salophen com-
plexes,8 DDQ,9 tetracyanoethylene (TCNE)10 and organotin phos-
phate condensates.11
Some of these methods suffer from the use of expensive, haz-
ardous and moisture sensitive catalysts, long reaction times and
use of high catalyst loading. In our earlier reports we have used
Fe(Cp)2PF6 as a catalyst for the cyanosilylation and the Strecker
reaction of ketones and aldehydes under solvent-free conditions
at room temperature.12 Recently, we have reported Fe(Cp)2BF4 as
a catalyst for the ring opening of epoxides with amines.13 Herein,
we report the use of commercially available Fe(Cp)2BF4 as an effi-
cient catalyst for the ring opening of epoxides with representative
alcohols at 25 °C (Fig. 1).
Fe(Cp)2BF4 (5 mol %) as a catalyst at 25 °C.14 The styrene oxide 1
was converted to 2-methoxy-2-phenyl ethanol (2a) in >99% after
5 min. The catalyst loading was decreased to 2 mol % and also gave
98% conversion after 40 min. The amount of methanol was
decreased to 8 equiv, styrene oxide 1 was completely consumed
and gave 81% yield of the desired product 2a with 19% other impu-
rities (Table 1, entry 4).
We have compared the reactivity of Fe(Cp)2BF4 (5 mol %) for the
methanolysis of styrene oxide with various catalysts under identi-
cal reaction conditions, which has been reported in the literature.
The catalyst Fe(Cp)2BF4 shows a better reactivity compared to
Fe(Cp)2PF6, InCl3, FeCl3, CoCl2, Ti(OiPr)4 and ZrCl4 (Table 1, entries
2 and 5–10). In the absence of catalyst the conversion of product
was determined to be only 4% after 24 h.
We have also studied the ring opening of styrene oxide 1 with
primary, secondary and tertiary alcohols using Fe(Cp)2BF4
(5 mol %) as a catalyst at 25 °C. The excellent conversions of sty-
rene oxide to 2-alkoxy-2-phenyl ethanol (2b–e) were observed in
15–30 min. (Table 2).
In our initial investigations, we have carried out the ring open-
ing of styrene oxide with methanol (5 mL, 61.8 equiv) using
The ring opening of 1,2-epoxyhexane 3 with methanol was car-
⇑
Corresponding author. Tel.: +91 11 276 67794; fax: +91 11 276 66605.
E-mail address: ssingh1@chemistry.du.ac.in (S. Singh).
ried out using Fe(Cp)2BF4 (2 mol %) as a catalyst at 25 °C.14 We
http://dx.doi.org/10.1016/j.tetlet.2014.05.017
0040-4039/Ó 2014 Elsevier Ltd. All rights reserved.
Please cite this article in press as: Yadav, G. D.; Singh, S. Tetrahedron Lett. (2014), http://dx.doi.org/10.1016/j.tetlet.2014.05.017

2
G. D. Yadav, S. Singh / Tetrahedron Letters xxx (2014) xxx–xxx
Table 1
have obtained four products in which the major two are regioiso-
meric products 4a and 4b, which are obtained from the ring open-
ing of 1,2-epoxyhexane 3 by an attack of methanol at the terminal
carbon, as well as the secondary carbon. Other by-products 4c and
4d were formed by the ring opening of 1,2-epoxyhexane (3) with
initially formed products 4a and 4b. The regioisomers 4a and 4b,
which were isolated and characterized by 1H NMR, 13C NMR spec-
troscopy and GCMS data. The by-products 4c and 4d were not pos-
sible to isolate by column chromatography and instead were
characterized only by GCMS. We have investigated the effect of
methanol on the rate of reaction and selectivity of the products.
The ring opening of 1,2-epoxyhexane (3) with methanol (1 equiv)
gave 91% conversion of epoxide and a ratio of regioisomeric prod-
uct 4a:4b of 2.47:1 with a poor selectivity (57%) (Table 3, entry 1).
The amount of methanol was increased up to 8 equiv was
increased the reaction time and the selectivity of products (4a
and 4b) was improved up to 95% with a comparable regioisomeric
ratio (Table 3, entries 2–5). When we used a large excess of
methanol (10 mL) the reaction time was increased to 20 h and
Ring opening of styrene oxide 1 with methanol using various catalystsa
OMe
O
OH
Catalysts
CH3OH
+
1
2a
Entry
Catalyst
Time
Conversionb (%)
1
2
3
4
5
6
7
8
Fe(Cp)2BF4
Fe(Cp)2PF6
Fe(Cp)2BF4
Fe(Cp)2BF4
InCl3
5 min
12 min
40 min
20 min
3 h
3 h
24 h
24 h
>99
99
98c
81d
81
99
9
FeCl3
CoCl2
Ti(OiPr)4
ZrCl4
—
9
10
11
20 min
20 min
24 h
98
91
4
(NH4)2Ce(NO3)6
No catalyst
a
Epoxide (2 mmol) was cooled to 0–5 °C then catalyst (5 mol %) and methanol
(61.8 equiv, 5 mL) were added and stirred at 25 °C for the specified time.
b
The conversion of epoxide to the product 2a was determined by GC.
Catalyst (2 mol %) was used.
Methanol (8 equiv) was used and epoxide was consumed, but 19% impurities
c
d
were observed.
Table 2
Fe(Cp)2BF4 catalysed ring opening of styrene oxide with different alcoholsa
OR
O
OH
Fe(Cp)2BF4
ROH
+
1
2b-e
b,c
Entry
R
Time (min)
Yield
of 2b–e (%)
1
2
3
4
Et
15
30
30
30
98 (99)
98 (>99)
99 (99)
98 (99)
nPr
iPr
tBu
a
Epoxide (2 mmol) was cooled to 0–5 °C, then Fe(Cp)2BF4 (5 mol %) and alcohols
(5 mL) were added and stirred at 25 °C for the specified time.
b
The reaction was monitored by GC and conversions are shown in parenthesis.
The % yield was measured after filtration of crude material through a pad of
c
Figure 2. Time dependent plot of conversion of 1,2-epoxyhexane (3) to products
catalysed by Fe(Cp)2BF4; [catalyst] = 0.045 M and [1,2-EH] = 22.50 Â 10À1 M.
Celite.
Table 3
Ring opening of 1,2-epoxyhexane (3) with methanol using Fe(Cp)2BF4 as a catalysta
OH
OMe
OMe
OH
+
4a
Fe(Cp)2BF4
Methanol, rt
4b
O
OMe
OH
O
+
3
O
HO
MeO
4c
4d
Entry
CH3OH
equiv
Time (h)
Conversion of epoxideb
Ratioc of 4a:4b
Selectivity of products 4a and 4bd (%)
Selectivity of products 4c and 4dd (%)
1
2
3
4
5
6
1
2
4
6
4.5
5
4.15
5.15
7
91
94
82
78
89
95
2.47:1
1.77:1
1:57:1
1.66:1
1.65:1
1.47:1
57
80
90
93
95
99
43
20
10
7
5
1
8
Excess (10 mL)
20
a
b
c
Epoxide (2 mmol) was cooled to 0–5 °C, Fe(Cp)2BF4 (2 mol %), then methanol were added and stirred at 25 °C for the specified time.
The conversion of epoxide to products was monitored by GC.
The ratio of regioisomers 4a:4b was determined by GC.
The products 4c and 4d were confirmed by GCMS and the % selectivity of products 4a and 4b = (GC area of 4a and 4b/GC area of all products 4a–4d) Â 100.
d
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G. D. Yadav, S. Singh / Tetrahedron Letters xxx (2014) xxx–xxx
3
Table 4
Effect of catalyst loading on the ring opening of 1,2-epoxyhexanea
Entry
Catalyst (mol %)
Time (h)
Conversion of epoxideb (%)
Ratioc of 4a:4b
Selectivity of product 4a and 4bd (%)
1
2
3
4
5
2
5
7
9
7
4
2.5
1.5
1.0
88
96
91
98
93
1.63:1
1.77:1
1.85:1
1.77:1
1.56:1
95
95
94
94
95
11
a
b
c
Epoxide (2 mmol) was cooled to 0–5 °C then Fe(Cp)2BF4 and methanol (8 equiv) were added, stirred at 25 °C for specified time.
The conversion of epoxide to products was monitored by GC.
The ratio of regioisomers 4a:4b was determined by GC.
The products 4c and 4d were confirmed by GCMS and the % selectivity of 4a and 4b = (GC area of 4a and 4b/GC area of all products 4a–4d) Â 100.
d
excellent selectivity of products (4a and 4b) was observed (Table 3,
entry 6).
We have also studied the effect of the catalyst loading for the
ring opening of 1,2-epoxyhexane (3) with methanol (8 equiv) at
25 °C. We varied, the catalyst concentration from 0.045 M to
0.248 M and plotting a graph for the conversion of 1,2-epoxyhex-
ane 3 versus time (Fig. 2), shows that the increase in catalyst con-
centration reduces the reaction time with the persistent selectivity
of the products 4a and 4b (Table 4). We have calculated the Kobs
and plotted with different concentrations of catalyst. The linear
graph of catalyst concentrations versus Kobs gives a clear indication
of a first order rate of reaction with dependence on catalyst con-
centration (Fig. 3).
We applied this methodology for the ring opening of a variety of
epoxides with methanol (1.05 equiv) as nucleophile and Fe(Cp)2
BF4 (5 mol %) as a catalyst at 25 °C.14 The ring opening of epichlo-
rohydrin (5) gave the desired product 6 in a 99% yield after 20 h
(Table 5, entry 1). The increased amount of methanol (8 equiv)
retards the reaction and gave only 42% conversion in 21 h (Table 5,
Figure 3. A plot shows linear dependence of Kobs with respect to the concentration
of catalyst for methanolysis of 1,2-epoxyhexane.
Table 5
a
Ring opening of various epoxides with methanol catalysed by Fe(Cp)2BF4
Entry
Epoxide
Product (s)
Time (h)
Yieldb (%)
O
OH
1
2
20
21
99
42c
Cl
Cl
OMe
5
6
O
OH
O
O
OMe
3
7
85
8
7
O
OH
4
5
10
23
98
O
34c
O
OMe
OH
9
10
O
O
O
OMe
OMe
6
7
30
20
83
O2N
11
O2N
12
O
OH
O
O
94
MeO
MeO
13
14
OH
O
8
9
6
4
81c
OMe
15
16
O
OH
OMe
+
OMe
OH
92c,d
C10H21
C10H21
C10H21
17
18a
18b
(continued on next page)
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4
G. D. Yadav, S. Singh / Tetrahedron Letters xxx (2014) xxx–xxx
Table 5 (continued)
Entry
Epoxide
Product (s)
Time (h)
Yieldb (%)
OH
10
11
4
4
33
O
77e
19
OMe
20
OH
O
12
0.5
97e
OMe
21
22
a
Epoxide (2 mmol) was cooled to 0–5 °C then Fe(Cp)2BF4 (5 mol %) and methanol (1.05 equiv) were added, stirred at 25 °C for the specified time.
Yield was measured after purification using column chromatography.
Methanol (8 equiv) was used.
The regioisomeric ratio was determined by GC and it was found to be 18a:18b (61:39).
Methanol (10 mL) was used.
b
c
d
e
OMe
O
Fe(Cp)2BF4
(5 mol%)
OH
OMe
OH
+
O
OMe
OH
+
CH3OH
+
+
C4H7
C4H7
2a
4a
4b
1 (1 mmol)
3 (1mmol)
16 mmol
% GC conversion
4
94
2
Scheme 1.
entry 2). The methanolysis of naphthylglycidyl ether (7) gave an
85% yield of regioselective product 1-methoxy-3-(naphthalen-2-
yloxy)propan-2-ol (8) after 7 h (Table 5, entry 3). The ring opening
of phenyl glycidyl ether (9) and para-substituted phenyl glycidyl
ethers (11 and 13) with methanol gave the corresponding products
in 83–98% yields after 10–30 h. The reactivity of methanolysis with
different phenyl glycidyl ethers was in the order phenyl glycidyl
ether > 4-methoxyphenyl glycidyl ether > 4-nitrophenyl glycidyl
ether.
Acknowledgments
S.S. acknowledges the financial assistance from the University
of Delhi under Research and Development grant and University
Science Instrumentation Centre (USIC), University of Delhi, India
for analytical data. G.D.Y. is thankful to CSIR for providing SRF.
Supplementary data
Supplementary data (1H, 13C NMR and GC data of all these com-
pounds) associated with this article can be found, in the online ver-
sion, at http://dx.doi.org/10.1016/j.tetlet.2014.05.017.
The amount of methanol was increased up to 8 equiv for the
ring opening of phenyl glycidyl ether, but
a poor yield of
product was obtained (Table 5, entry 5). The methanolysis
of 1,5-cyclooctadiene mono oxide (15) afforded 81% yield of
trans-5-methoxy-cyclohex-1-en-4-ol (16) after 6 h (Table 5, entry
8). The ring opening of 1,2-epoxydodecane (17) with methanol
(8 equiv) gave a 92% total yield of both regioisomers after 4 h
(Table 5, entry 9). 1-Methoxydodecan-2-ol (18a) was obtained as
the major regioisomer and 2-methoxydodecan-1-ol (18b) as the
minor regioisomer (61:39). The ring opening of cyclopentene oxide
and cyclohexene oxide by excess methanol (123.6 equiv, 10 mL)
gave trans-2-methoxy cyclopentanol (20) and trans-2-methoxy
cyclohexanol (21) in 77–97% yields after 0.5–4 h (Table 5, entries
11 and 12). The smaller amount (1.05 equiv) of methanol led to
the by-product formation and a poor yield (33%) of desired product
(20) was obtained (Table 5, entry 10).
We have also conducted a competitive experiment for the ring
opening of 1,2-epoxyhexane (1 mmol) and styrene oxide (1 mmol)
with methanol (16 mmol) using Fe(Cp)2BF4 (5 mol %). We have
selectively obtained product 2a (94%) after 5 min (Scheme 1).
In summary, we have applied Fe(Cp)2BF4 as a catalyst for the
methanolysis of a range of aliphatic and aromatic containing epox-
ides at 25 °C. The ring opening of styrene oxide with different alco-
hols gave excellent yields of the corresponding b-alkoxy alcohols.
The substrates like styrene oxide, cyclohexene oxide and cyclopen-
tene oxide are more reactive, required the dilute reaction medium
to give highly selective desired products. Other epoxide like glyc-
idyl ethers, epichlorohydrin, 1,2-epoxy hexane and 1,2-epoxy
dodecane required a concentrate reaction medium to afford better
yield after short reaction time. The methodology is working well
with a variety of substrates with methanol as the nucleophile.
References and notes
1. (a) Smith, J. G. Synthesis 1984, 629; (b) Ager, D. J.; Prakash, I.; Schaad, D. R.
Chem. Rev. 1996, 96, 835; (c) Otera, J.; Yoshinago, Y.; Hirakawa, K. Tetrahedron
Lett. 1985, 26, 3219; (d) Tokunaga, M.; Larrow, J. F.; Kakiuchi, F.; Jacobsen, E. N.
Science 1997, 277, 936; (e) Iranpoor, N.; Adibi, H. Bull. Chem. Soc. Jpn. 2000, 73,
675; (f) Posner, G. H.; Rogers, D. Z. J. Am. Chem. Soc. 1977, 99, 8214; (g)
Fringuelli, F.; Piermatti, O.; Pizzo, F.; Vaccaro, L. J. Org. Chem. 1999, 64, 6094; (h)
Yadav, J. S.; Reddy, A.; Ramesh, N. A. V.; Reddy, B. V. S. J. Mol. Catal. A: Chem.
2007, 261, 207.
2. Chakaraborty, T. K.; Chattopadhyay, A. K.; Samanta, R.; Ampapathi, R. S.
Tetrahedron Lett. 2010, 51, 4425.
3. (a) Corey, E. J.; Cheng, X. M. The Logic of Chemical Synthesis; John Wiley: New
York, 1989; (b) Kino, T.; Hatanaka, H.; Hashimato, M.; Nishiyama, M.; Goto, T.;
Okuhara, M.; Kohsaka, M.; Aoki, H.; Imanaka, H. J. Antibiot. 1987, 40, 1249.
4. (a) Creteche, L. H.; Pittenger, W. H. J. Am. Chem. Soc. 1924, 46, 1503; (b)
Ashburn, H. V.; Collect, A. R.; Lazell, C. L. J. Am. Chem. Soc. 1935, 57, 1862; (c)
Winstein, S.; Henderson, R. B. J. Am. Chem. Soc. 1943, 65, 2196; (d) Reeve, W.;
Christoffer, I. J. J. Am. Chem. Soc. 1950, 72, 1480.
5. FeCl3 supported on silica: (a) Iranpoor, N.; Tarrian, T.; Movahedi, Z. Synthesis
1996, 1473; Polymer supported ferric chloride: (b) Reddy, Y. V.; Reddy, S. M.;
Tammishetti, S. React. Funct. Polym. 2005, 64, 157; Mesoporous and nanoporous
aluminosilicates: (c) Robinson, M. W. C.; Davies, A. M.; Buckle, R.; Mabbett, I.;
Taylor, S. H.; Graham, A. E. Org. Biomol. Chem. 2009, 7, 2559; Robinson, M. W. C.;
Davies, A. M.; Mabbett, I.; Apperley, D. C.; Taylor, S. H.; Graham, A. E. J. Mol.
Catal. A: Chem. 2009, 314, 10; Dehydrated alumina: (d) Posner, G. H.; Roger, D.
Z.; Kinzig, C. M.; Gurria, G. M. Tetrahedron Lett. 1975, 42, 3597; Heterodimetalic
coordination polymer: (e) Kumar, G.; Singh, A. P.; Gupta, R. Eur. J. Inorg. Chem.
2010, 5103; Polymer-supported Ru and Fe complexes: (f) Lee, S. H.; Lee, E. Y.;
Yoo, D. W.; Hong, S. J.; Lee, J. H.; Kwak, H.; Lee, Y. M.; Kim, J.; Kim, C.; Lee, J. K. J.
New Chem. 2007, 31, 1579; (g) Nafion, H.; Olah, G. A.; Fung, A. P.; Meidar, D.
Synthesis 1981, 280; Zirconium doped silica (h) Barreca, D.; Coplet, M. P.;
Graham, A. E.; Holmes, J. D.; Morris, M. A.; Seraglia, R.; Spalding, T. R.; Tondello,
E. Appl. Catal. A: Gen. 2006, 304, 14; Sulfated yttria–zirconia: (i) Kahandal, S. S.;
Please cite this article in press as: Yadav, G. D.; Singh, S. Tetrahedron Lett. (2014), http://dx.doi.org/10.1016/j.tetlet.2014.05.017

G. D. Yadav, S. Singh / Tetrahedron Letters xxx (2014) xxx–xxx
5
Kale, S. R.; Disalea, S. T.; Jayram, R. V. Catal. Sci. Technol. 2012, 2, 1493; Iron
oxide-pillared clay: (j) Trikittiwong, P.; Sukpirom, N.; Chayasiri, W. J. Mol. Catal.
resulting mixture was stirred at room temperature for specified time. The
reaction progress was checked by GC. After completion of the reaction the
crude product was purified by column chromatography or passed through a
pad of celite.
A: Chem. 2013, 378, 76;
(NH4)8[CeW10O36]Á20H2O: (k) Mirkhani, V.;
Tangestaninejad, S.; Yadollahi, B.; Alipanah, L. Tetrahedron 2003, 8213;
K5[CoW12O40]Á3H2O: (l) Tangestaninejad, S.; Moghadam, M.; Mirkhani, V.;
Yadollahi, B.; Mirmohammadi, S. M. R. Monatsh. Chem. 2006, 137, 235;
Graphene oxide: (m) Dhakshinamoorthy, A.; Alvaro, M.; Concepcion, P.;
Fornes, V.; Garcia, H. Chem. Commun. 2012, 48, 5443; Copper based metal-
organic framework: (n) Jiang, D.; Mallat, T.; Krumeich, F.; Baiker, A. J. Catal.
2008, 57, 390; Saponite clays: (o) Guidotti, M.; Psaro, R.; Ravasio, N.; Sgobba,
M.; Carniato, F.; Bisio, C.; Gatti, G.; Marchese, L. Green Chem. 2009, 11, 1173;
Sulfur and iron co-doped titanoniobate nanosheets: (p) Zhang, L.; Hu, C.; Zhang,
J.; Cheng, L.; Zhai, Z.; Chen, J.; Ding, W.; Hou, W. Chem. Commun. 2013, 49, 7507.
6. CuBF4: (a) Barluenga, J.; Vazquez-Villa, H.; Ballesteros, A.; Gonzalez, J. M. Org.
Lett. 2002, 4, 2817; and Capes, A. S.; Crossman, A. T.; Webster, L. A.; Ferguson,
M. A. J.; Gilbert, I. H. Tetrahedron Lett. 2011, 52, 7091; SnCl4: (b) Moberg, C.;
Rakos, L.; Tottie, L. Tetrahedron Lett. 1992, 33, 2191; InCl3: (c) Kim, B. H.; Piao,
F.; Lee, E. J.; Kim, S.; Jun, Y. M.; Lee, B. M. Bull. Korean Chem. Soc. 2004, 25, 881;
FeCl3: (d) Iranpoor, N.; Salehi, P. Synthesis 1994, 1152; Mg(HSO4)2: (e) Salehi, P.;
Khodaei, M. M.; Zolfigol, M. A.; Keyvan, A. Synth. Commun. 2003, 33, 3041;
Er(OTf)3: (f) Dalpozzo, R.; Nardi, M.; Oliverio, M.; Paonessa, R.; Procopio, A.
Synthesis 2009, 20, 3433; TiCl3(OTf): (g) Iranpoor, N.; Zeynizadeh, B. Synth.
Commun. 1999, 26, 1017; Al(OTf)3: (h) Williams, D. B. G.; Lawton, M. Org.
Biomol. Chem. 2005, 3, 3269; Fe(ClO4)3: (i) Salehi, P.; Seddighi, B.; Irandoost, M.;
Behbahani, F. K. Synth. Commun. 2000, 30, 2967; Ceric ammonium nitrate
(CAN): (j) Chapuzet, J. M.; Beauchemin, S.; Daoust, B.; Lessard, J. Tetrahedron
1996, 52, 4175.
Data for new compounds
Trans-8-Methoxycyclooct-4-enol (16): Colorless liquid (126 mg, 81%). 1H NMR
(400 MHz, CDCl3): d = 5.53–5.50 (m, 2H), 3.63–3.61 (m, 1H), 3.22 (s, 3H), 3.15–
3.14 (m, 1H), 2.62 (m, 2H), 2.08–2.01 (m, 4H), 1.52–1.50 (m, 2H) ppm. 13C NMR
(100 MHz, CDCl3): d = 129.44, 128.31, 83.81, 72.75, 57.42, 32.34, 28.44, 22.94,
22.49 ppm. IR (In CH2Cl2): 3435, 2925, 1640, 1094, 718 cmÀ1. HRMS (ESI): m/z
[M+Na]+ calcd for C9H16NaO2: 179.1048; found: 179.1062.
1-Methoxydodecan-2-ol (Major regioisomer 18a): Brown liquid (237 mg, 55%).
1H NMR (400 MHz, CDCl3): d = 3.75 (m, 1H), 3.38–3.34 (m, 4H), 3.22–3.20 (m,
1H), 2.44 (br s, OH, 1H), 1.40–1.22 (m, 18H), 0.84 (t, J = 6.96 Hz, 3H) ppm. 13C
NMR (100 MHz, CDCl3): d = 77.08, 70.21, 58.92, 33.08, 31.85, 29.63, 29.55,
29.51, 29.27, 25.48, 25.29, 22.63, 14.04 ppm. IR (In CH2Cl2): 3431, 2925, 2854,
1453, 1113, 721, cmÀ1 HRMS (ESI): m/z [M+Na]+ calcd for C13H28NaO2:
.
239.1987; found: 239.1984.
2-Methoxydodecan-1-ol (Minor regioisomer 18b): Brown liquid (159 mg, 37%).
1H NMR (400 MHz, CDCl3): d = 3.60 (dd, J = 12.45, 3.66 Hz, 1H), 3.41 (dd,
J = 11.72, 5.86 Hz, 1H), 3.33 (s, 3H), 3.16 (m, 1H), 2.25 (br s, OH, 1H), 1.49–1.14
(m, 18H), 0.80 (t, J = 6.22 Hz, 3H) ppm. 13C NMR (100 MHz, CDCl3): d = 81.63,
63.84, 56.97, 31.83, 30.21, 29.77, 29.53, 29.49, 29.26, 25.46, 25.27, 22.61,
14.04 ppm. IR (In CH2Cl2): 3431, 2925, 2854, 1453, 1113, 721 cmÀ1. HRMS
(ESI): m/z [M+Na]+ calcd for C13H28NaO2: 239.1987; found: 239.1984.
1-Methoxyhexan-2-ol (Major regioisomer 4a): Brown liquid (156 mg, 59%). 1H
NMR (400 MHz, CDCl3): d = 3.67 (m, 1H), 3.32–3.28 (m, 5H), 1.39–1.23 (m, 6H),
0 .81 (t, J = 7.32 Hz, 3H) ppm. 13C NMR (100 MHz, CDCl3): d = 78.19, 71.12,
59.89, 33.84, 28.81, 23.70, 14.95 ppm. IR (In CH2Cl2): 3421, 2929, 2871, 1465,
1099, 730 cmÀ1. GCMS (ESI): m/z [M-OCH3]+ calcd for C6H13O: 101; found: 101.
2-Methoxyhexan-1-ol (Minor regioisomer 4b): Brown liquid (98 mg, 37%). 1H
NMR (400 MHz, CDCl3): d = 3.61 (dd, J = 10.98, 2.96 Hz, 1H), 3.41 (dd, J = 10.98,
5.88 Hz, 1H), 3.33 (s, 3H), 3.20–3.17 (m, 1H), 1.26–1.23 (m, 6H), 0.83 (t, J = 7.32,
Hz, 3H) ppm. 13C NMR (100 MHz, CDCl3): d = 81.68, 63.80, 56.97, 30.09, 27.61,
7. Sn(IV)(TPP)(BF4)2: (a) Moghadam, M.; Tangestaninejad, S.; Mirkhani, V.; Baltork,
I. M.; Taghavi, S. A. Catal. Commun. 2007, 8, 2087; V(IV)(TPP)(OTf): (b) Taghavi, S.
A.; Moghadam, M.; Baltork, I. M.; Tangestaninejad, S.; Mirkhani, V.;
Khosropour, A. R.; Ahmadi, V. Polyhedron 2011, 30, 2244.
8. Venkatasubbaiah, K.; Feng, Y.; Arrowood, T.; Nickias, P.; Jones, C. W. Chem. Cat.
Chem. 2013, 5, 201.
9. Iranpoor, N.; Mohammadpour, I. Tetrahedron Lett. 1990, 31, 735.
10. Uyanik, C.; Hanson, J. R.; Hitchcock, P. B.; Lazar, M. A. Tetrahedron 2005, 61,
4323.
22.80, 13.90 ppm. IR (In CH2Cl2): 3421, 2929, 2871, 1465, 1099, 730 cmÀ1
.
GCMS (ESI): m/z [M-OCH3]+ calcd for C6H13O: 101; found: 101.
11. Otera, J.; Niibo, Y.; Nozaki, H. Tetrahedron 1991, 47, 7625.
1-Methoxy-3-(4-nitrophenoxy)propan-2-ol (12): Yellow liquid (188 mg (83%).
1H NMR (400 MHz, CDCl3): d = 8.10–8.08 (m, 2H), 6.93–6.90 (m, 2H), 4.16–4.04
(m, 3H), 3.54–3.50 (m, 2H), 3.35 (s, 3H) ppm. 13C NMR (100 MHz, CDCl3):
d = 163.47, 141.35, 125.66, 114.34, 73.06, 69.58, 68.48, 59.08 ppm. IR (In
CH2Cl2): 3420, 2933, 2860, 1451, 1095, 846 cmÀ1. HRMS (ESI): m/z [M+Na]+
calcd for C10H13NaNO5: 250.0691; found: 250.0701.
12. (a) Khan, N. H.; Agrawal, S.; Kureshy, R. I.; Singh, S.; Abdi, S. H. R.; Jasra, R. V. J.
Organomet. Chem. 2007, 692, 4361; (b) Khan, N. H.; Agrawal, S.; Kureshy, R. I.;
Singh, S.; Abdi, S. H. R.; Suresh, E.; Jasra, R. V. Tetrahedron Lett. 2008, 49, 640.
13. Yadav, G. D.; Chauhan, M. S.; Singh, S. Synthesis 2014, 629.
14. General procedure: The catalyst Fe(Cp)2BF4 (5 mol %) was added to a cooled
epoxide (2 mmol), then methanol (1–8 equiv or 5 mL or 10 mL) was added. The
Please cite this article in press as: Yadav, G. D.; Singh, S. Tetrahedron Lett. (2014), http://dx.doi.org/10.1016/j.tetlet.2014.05.017